The entangled gamma photons interact with a graviton and induce a magnetic field, may get gravitationally-induced decoherence of the entanglements, in a quantum gravity Lagrangian

A quantum gravity Lagrangian encodes how the graviton field behaves and interacts with matter fields like photons to get gravitationally-induced decoherence of the entanglements. General relativity is usually described using the metric, but this form isn't very friendly for canonical quantization. The process of converting a classical theory into a quantum one. Ashtekar variables recast general relativity into a form more similar to gauge theories like Yang-Mills (think electromagnetism or the Standard Model), making gravity more quantizable.